AJM Turbocharger: Different Cause?

Hello and have a wonderful day!
I've been thinking about what would be better for our turbos: variable geometry turbines (VTGs).
"It's started. I didn't want to deal with the theory that these things just always get stuck."
do not satisfy.
Here are a few measurements I took.
I hope an administrator can upload the pictures for me here! (Thank you.)
I have installed two pressure sensors and a distance sensor.
1) P- solenoid valve --red
2) Vacuum system (P-side) -- blue.
3) Route - VTG -- yellow.
4) Zero line (0 bar ATM; VTG standby mode).
The first image is just for orientation!
Engine being shut down!
VTG is starting with some momentum!
The vacuum system remains almost stable at -0.8 bar (with some oscillations).
Valve pressure reduction complies with VTG standards and is set to zero!
Therefore, you can't see any issues related to VTG (presumably a specific system or technology) at all?
The sensors are calibrated and have a class of 0.1, so they are not just estimates!

http://www.webhosting4free.biz/messknecht/motorausschalten.jpg

Now for the permeability test!
Run my measurement equipment and VAG-COM software simultaneously so that you can see the data.
How the suppressors behave in relation to the VTG (Variable Temperature Gas) strut!
Okay, let's see if any of the scholars on board can come up with a rhyme here.
to make it happen!
If there's interest, I can create a more elaborate and visually appealing experimental setup later on.
For example: engine speed, VTG (Variable Turbine Geometry) position, turbocharger pressure, and vacuum control valve.
And all of this is integrated into a measurement system with a sampling rate of 2ms or something like that!
Please provide suggestions!
Now, let's move on to the two images.
It's the same acceleration process! Third gear, 1000-3800 rpm, full throttle!

http://www.webhosting4free.biz/messknecht/vtg-weg-vent-druck-11log.jpg
http://www.webhosting4free.biz/messknecht/log-11-3gang-1000-3800rpm.jpg

What I see as borrowed elements in this area are mainly the solenoid valve and the linkage.
"Great job! However, the pressure is really high! There are two possibilities..."
The pressure sensor from the car is either scrap (which I doubt), or it's a good turbocharger that can be salvaged.
Not enough air! Please don't! My air filter is new!
So, what do you think of this theory?

Here's another nice picture that might explain Herwig's problem with his minute of silence!
When switching from idling to full throttle at 2000 rpm.
When you accelerate, the VTG (Variable Turbine Geometry) briefly extends to its maximum position and then retracts.
Progress is being made!

http://www.webhosting4free.biz/messknecht/Beschleunigungvonschleppzuvollast.jpg

Looking forward to your suggestions!

Unfortunately, there's a problem with the links.

Accessing this data from external sources is not permitted.

It's not really a big deal. Just reload the page, as if you had typed in the address manually.
I can't read the dark blue text in the chart; what was measured there?
Otherwise, this is a sensible approach that the VAG group should have implemented as standard. Then we wouldn't have all the problems with unrecognized sticking VTGs (Variable Turbine Geometry) and AGR (Exhaust Gas Recirculation) valves.

@christians
Blue represents the vacuum pressure provided by the vacuum pump (which is -0.8 bar in this case).
Okay, so right after the connection between the pump and the brake booster.
As I said, this is just the beginning. I also suspected that the vacuum pump might be vibrating. But as you can see, it's not the cause!
I now think the turbo isn't getting enough air.
Due to the extremely narrow intake nozzle.
"I've experienced something similar to a pressure fluctuation during compressor measurements before."
Seen it! Of course, it could also be another delusion!
Best regards and have a lovely Sunday!

messknecht wrote:

... Therefore, you can't see any issues related to VTG (presumably a specific system or technology) at all? ...

So, if I look at your graphics...

My old master used to say: "He who measures too much ends up measuring nonsense."

Your experimental setup is commendable... Excellent, but the conclusions you draw from it... 0 points!

Your VTG is stuck in the most exquisite way! [EDIT: I removed the next sentence; Bertil]


I took the liberty of cropping your graphics to focus on the essential elements and slightly distorting them along the vertical axis. This will make the overall image clearer.

At point A, the pressure in the VGT control chamber increases slightly to limit the boost pressure (towards a minimum boost pressure). What does your VGT do? It gently and peacefully stays in the "Maximum Boost Pressure" position, then later, with jolts and vibrations of the pressure sensor, it follows the direction towards a minimum boost pressure.
At position B, the pneumatic system briefly increases the boost pressure again. Your VTG follows with a short delay (which is acceptable so far). However, when the pneumatic system returns to the minimum boost pressure and remains there almost constantly, your pressure sensor continues moving towards the minimum pressure (point C). It hadn't yet reached its minimum limit. Something is definitely stuck.

The movement of the VTG mechanism and the pressure inside the VTG container should always be closely correlated (a slight time delay is acceptable, see point B). This is a rigid system.

Bertil wrote:

The movement of the VTG mechanism and the pressure inside the VTG container should always run absolutely parallel to each other... It is a rigid system.

Sure.
And therefore, I don't quite understand (as of now) why such an elaborate process was undertaken instead of using the simplest method (which would involve using a large syringe to suction and observing the movement of the VTG) .

Hello!
I'm not quite sure how I should structure my answer.
Please don't categorize me as unintelligent or anything like that.
I was just about to ask you to delete this thread, but I think...
I should explain why I posted this measurement here.
Okay, first of all, @Bertil.
You really put in a lot of effort to create and comment on the excerpt.
What you may not know is that the vacuum at the valve point...
The pressure is -0.65 bar, and my VTG rod is already fully extended at -0.54 bar.
It can only start to "settle in" after you experience what you describe as a moment of realization or awakening.
What you describe as "stuttering" is actually the brief (170ms) period of stabilization.
It's better to see this in the correct measurement program.
I checked my VTG (Variable Turbine Geometry) vanes using a vacuum pump.
Ulf should have read it, as he responded to me on a different topic.
replied.
I was referring to point B in the image, and that's where I wanted the measurement to end.
The vacuum is relatively stable, and the rod moves easily up and down.
I just wanted to spark a small discussion.
Is it in the AJM?
"It only ever shows the hanging VTG (vertical travel gauge) reading, or it could be due to insufficient force from the pressure sensor in the lower chamber, combined with air that doesn't flow quickly enough."
"the ones responsible for the less-than-ideal printing results."
Okay? Thank you.

messknecht wrote:

I checked my VTG struts using a vacuum pump! Ulf should have read it, as he responded to me on my other topics.

It might be, but I read and write so much here that I can't always remember everything . Also, I was on vacation for the last 3 weeks.

Quote:

I actually just wanted to spark a small discussion about whether the hanging VTG (Variable Turbine Geometry) is always the only cause, or if insufficient force from the pressure sensor and air that doesn't flow quickly enough could also be responsible for the undesirable pressure curves.

If the pneumatic system doesn't provide enough flow to change the pressure in the VTG chamber "quickly enough" (which would need to be defined more precisely), then the resulting symptoms are likely very similar to those of a stuck VTG.

Here are some potential primary causes that immediately come to mind:
1. Incorrect interpretation of the system, e.g., using hoses or valves with insufficient diameter.
2. Defects such as bent or leaking pneumatic hoses, stuck solenoid valves, etc.

messknecht wrote:

... Please don't categorize me as uncooperative or anything like that.

No, I hadn't planned to.

Quote:

I was just about to ask you to delete this thread, but I think... I should explain why I posted this measurement here.

Deletions are not normally allowed here.

Quote:

Okay, first of all, @Bertil. You really put in a lot of effort to create and comment on the excerpt. What you may not know is that the vacuum at the valve point... The pressure is -0.65 bar, and my VTG rod is already fully extended at -0.54 bar. It can only start to "settle in" after you experience what you describe as a moment of realization or awakening.

Here he is, the one to blame.
Your VTG valve is malfunctioning. It's reaching full open too early. Adjusting the linkage might help.
There is a technical article available on how to adjust the linkage.

Quote:

What you describe as "jerking" is the brief (170ms) stabilization of the valve pressure. It's better visualized in a proper measurement program.

It might be, but the VTG path doesn't run parallel to the attached printout. Therefore, something must be wrong.

Quote:

I checked my VTG (Variable Turbine Geometry) vanes using a vacuum pump. Ulf should have read it, as he responded to me on another topic.

Unfortunately, using a vacuum pump for testing has a certain disadvantage. You can't simulate every operating condition with it. The only solution is a complex setup like the one you created.

Quote:

I was referring to point B in the image, and that's where I wanted the measurement to end. The vacuum is relatively stable, and the rod moves easily up and down.

As far as I can see, the linkage is actually moving in a direction that suggests "less boost pressure," even though the control pressure remains constant.

Quote:

I actually just wanted to spark a discussion about whether the "hängende VTG" (presumably referring to a specific technical term) is always the only cause of undesirable pressure fluctuations in the AJM system, or if factors like insufficient force from the differential pressure sensor and air that doesn't flow quickly enough could also be responsible.

Your problem doesn't specifically relate to the AJM, but rather to all VTG turbos.
The pneumatic VTG system is inherently quite noisy. If even one parameter is incorrect, or if something gets stuck temporarily, it becomes very difficult to understand what's happening.
Your measurements clearly demonstrate how the VTG (Variable Transmission Gear) works and where potential errors can occur.

ulf wrote:

messknecht wrote: I checked my VTG struts using a vacuum pump! Ulf should have read it, as he responded to me on my other topics. It might be, but I read and write so much here that I can't always remember everything ...

"...especially since this statement was made in a different thread. It's always bad to extend the same problem across two (or more) threads. This creates significant confusion."

Thank you for this excellent answer!
The regulated boost pressure is really at the lower limit of the tolerance range (if you can even call it a range).
I'm going to start looking for a new one (a bigger one).
(Make a pressure vessel).
It might be difficult to find, but the car is still running!
Thank you.

messknecht wrote:

I have installed two pressure sensors and a distance sensor. 1) P- solenoid valve --red 2) Vacuum system (P-side) -- blue. 3) Route - VTG --yellow

Could you tell me where you got the print from?
Should I check the solenoid valve or the VTG unit?

I only just now found the red and blue lines by brightening your graphics... and I can quite well imagine that the general lag of the VTG container compared to the valve pressure is a consequence of a bottleneck in the hose between the valve and the container, which causes all (valve-controlled) pressure changes to reach the container with delays.

A kink or foreign object in the tube insertion nozzle of the can could naturally cause the same effect...

I tapped into the valve using a tee fitting at the top.
Of course, the hose leading to the VTG canister will also act as a narrow restriction.
It's not really that thick.

messknecht wrote:

Of course, the hose to the VTG canister still needs to be added as a tight connection. It's not really thick, is it?

On the other hand, I can only interpret the sudden sharp increase in the VTG reading on the right side of the image, without any preceding pressure change that would suggest it, as a significant mechanical jam.

The somewhat jerky reaction of the VTG to consistent pressure changes also indicates that your VTG is at least temporarily jammed (see Bertil's response/the movement pattern between point A and B).

Naturally, blockages can also cause delayed reactions to pressure changes, which means that the assumption of a narrow passage might be incorrect.

Hi!
Today, I'm going to start looking for a new vintage tin container.
Does anyone happen to know where I might be able to find it in the Hanover area?
Bertil's answer about the weakened can is probably the most obvious one.
The funny thing is, everything works perfectly when I'm standing.
All distances measured multiple times! But when it's under load, then...
It just looks really bad.
I also want to polish the VTG (valve cover) to a high gloss while I'm already changing it.
That poor thing has already accumulated 165,000 km of soot.
I would be grateful for any tips on where I can find a new, larger container.

@Bertil:

Am I understanding correctly that the spring force must be as large as usual?
Is the program pre-defined, or does the engine control unit always 'malfunction' first?

How about the opposite scenario, with the impeller and the forces acting on the guide vanes inside? Is it really possible to...?
It is assumed that a functioning charger will not affect any operating states.
Is something pulling on the VTG rod in one direction or another, disrupting the adjustment?

What I mean is: A perfect front-wheel drive system would function independently of...
it's always easy to steer, but in practice, things are often different.
Undesirable forces are at play, pulling at the steering wheel...

Sure, here is the translation of the text from German to English:

'Hello.'
Herwig.